Objectives : The study was designed to observe the effect of Polygalae Radix Preparata Cum Glycyrrhizae Radix on 4-Hydroxynonenal (4-HNE)-induced apoptosis in PC-12 cell.Methods : A cytotoxic test on Polygalae Radix Preparata Cum Glycyrrhizae Radix (PG) was conducted and another MTT assay was conducted to observe the cytoprotective effect against 4-HNE that cause oxidative stress. In addition, in order to observe the expression of Bax, Bcl-2, Caspase-3 and TNF-α protein involved with apoptosis, western blot was conducted.Results : The groups treated with 25 ㎍, 50 ㎍ and 100 ㎍ of PG water extract had no toxicity for PC-12 cell. The groups treated with 25 ㎍, 50 ㎍ and 100 ㎍ of PG water extract showed a significant increase of cell survival rate in comparison with the control group injected by only 4-HNE. The groups treated with 25 ㎍ and 50 ㎍ of PG water extract showed a significant supression on increase of Bax protein expression in the control group. The group treated with 100 ㎍ of PG water extract showed a significant promotion on decrease of Bcl-2 protein expression in the control group. The group treated with 50 ㎍ of PG water extract showed a significant supression on increase of Caspase-3 protein expression in the control group. The group treated with 25 ㎍ of PG water extract showed a significant supression on increase of TNF-α protein expression in the control group.Conclusions : These results suggest that Polygalae Radix Preparata Cum Glycyrrhizae Radix is effective in reducing apoptosis by 4-HNE-dameged cell.